The present invention relates to electroless plating of polyamides, in particular, to providing a surface uniformly receptive to metals which catalyze electroless deposition of nickel and copper.
The benefits of electroless plated, non-conductive articles, particularly plastic articles, are well known. In the finished product, the desirable characteristics of the plastic and the metal are combined to offer thereby the technical and aesthetic advantages of each.
Polymeric substrates are conventionally plated by pre-conditioning the surface by contact with an aqueous solution of at least one organic compound active for "conditioning" or "pre-etching" the surface of the plastic, etching with a strong oxidizing acid or base, seeding the surface with a noble metal catalyst, e.g., a palladium chloride solution, then immersing the seeded surface in an autocatalytic electroless plating solution where an initial coating of a conductive metal, e.g. copper or nickel, is established by chemical deposition. The metal deposit acts as a buss to allow a thicker coating of metal to be built up electrolytically.
Attempts to adapt conventional procedures for electroless plating of polymers to polyamides by us have resulted in a failure to achieve a uniform adherent coat of metal. Having found conventional electroless plating procedures ineffective, a quest was initiated to discover a procedure to enable uniform coating of polyamides with electroless deposited metals.